The most common, naturally occurring anthrax infection. May be transmitted via skin contact with contaminated meat, wool, hides, or leather from infected animals. Incubation is from 1 to 12 days. Infection occurs through scratches or skin abrasions.

Infection appears as a raised bump resembling a spider bite. Within 1 to 2 days, it develops into a blister and then a painless ulcer, with a black necrotic (dying) area in the center. The lesion may cause fever, malaise, and headache. Lymph glands in the area may swell.

Anthrax spores must be aerosolized to cause inhalational anthrax. It is contracted by inhaling spores and occurs in workers handling infected animal hides, wool, and fur. The number of spores that cause infection is unknown. Incubation period is unclear, but may range from 1 to 7 days or up to 60 days.

Inhalation anthrax resembles a viral respiratory illness. Initial symptoms include sore throat, mild fever, muscle aches, and malaise. Symptoms may progress to respiratory failure and shock with meningitis. After incubation of 1 to 7 days, the onset of inhalation anthrax is gradual.